by Kyle Sweet, The Sanctuary Golf Club, Florida Master Naturalist
The dragonfly can be traced back in time some 300 million years and of all of the insects I see on Sanibel may be the most abundant. This is especially true if spending a lot of time along the edge of a lake on the golf course or an area freshwater wetland.
Most of the dragonflies life is spent as a nymph (the immature form of an insect that does not change greatly as it grows), living underwater for a year or more. During this time, it molts several times and eventually crawls up out of the water and molts one last time, emerging from its old skin as an adult with functional wings. Unlike a butterfly, the dragonfly does not have a pupal stage before becoming an adult, so in turn the metamorphosis is considered “incomplete” or “gradual”.
Without a doubt, the dragonfly has quite large eyes compared to the rest of their body. Each compound eye is composed of nearly 28,000 individual units and cover most of the head. With eyes that large, more than 80% of their brain is devoted to analyzing visual information. Their vision is exceptional, encompassing almost every angle except directly behind them.
Dragonflies have two pairs of elongated membranous wings with a strong cross vein and many other veins that criss cross in the wings. This structure adds strength and stability to the wings. What’s really awesome is that it’s very visible with the naked eye! Such great wings provide for them to be great fliers. Their ability to fly straight up and down, hover still like a helicopter and dart quickly at speeds up to 30 mph makes them incredible hunters.
Dragonflies feed on a wide variety of other flying insects such as midges, mosquitoes, butterflies, moths and a close relative, the damselfly. The dragonfly has been documented as one of the world’s most efficient hunters, catching up to 95% of the prey it pursues.
Even with the excellent agility and speed, the dragonfly can be preyed upon by agile flyers such as the American Kestrel, Merlin, flycatchers and swallows. In the water, as a nymph, various species of ducks and herons eat them as well as newts, frogs and fish.
Dragonflies, particularly the males, are territorial and will perch over an insect-rich feeding ground defending it against others from its same species. In addition to defending an area for a food source, they also defend a territory for breeding if the area has specific water qualities, plant species or a preferred substrate for egg laying.
Dragonflies have a very wide variety of colorations, with some having brilliant iridescent or metallic colors. When they are in flight, it’s tough to appreciate the colorations but as with birding, a good camera with telephoto lens or a spotting scope provides the opportunity to view closely and really appreciate this ancient insect. Birding is for birds as Oding is for dragonflies. The term comes from the order that is belongs to, Odonata. So, happy oding! You’re sure to see one of these interesting insects very soon!